1. Field of the Invention
The present invention pertains, generally to the field of permeable membranes and packaging for volatile materials, such as fragrances and other aromatic products, and more particularly, to permeable multilayer membranes and packages, which allow the controlled release of aromatic products over a period of time. The package prevents the escape of the aromatic fragrance until the consumer desires to start the release of the fragrance by peeling back the package to expose the permeable membrane.
2. Description of the Art
The controlled time release of very volatile substances, such as fragrances and other aromatic products, presents a number of packaging problems. Room “air fresheners” or fragrances have usually been packaged in glass bottles or vials. The fragrance is released into the atmosphere by transmission through an absorbent wick, which is capped until the time of use. However, glass bottles are bulky and breakable. It is generally not economical to package fragrances in small quantities inside glass containers, because the cost of the glass container is high.
One proposed alternative method of packaging room fragrances is to place a breakable glass vial within a plastic container formed of a material that is permeable to the vapors of the volatile fragrance. The user deliberately breaks the glass vial to allow the fragrance liquid to seep into the absorbent pad and the vapors from the liquid slowly diffuse into the atmosphere through the permeable outer container. These containers may be subject to accidental breakage of the glass vial during shipping and handling, as well as to a possible puncture of the container by broken glass. The manufacturing costs are increased by the use of the glass vial within the container.
Other fragrance dispensers utilize sealed packages, which are opened by peeling back a covering foil to expose a perforated panel covering an absorbent pad filled with the fragrance liquid. The costs of such containers make them generally inappropriate for dispensing small amounts of the fragrance. It is also somewhat difficult to obtain controlled release of the fragrance at a fairly constant rate over the life of the product, because the liquid is directly exposed to the atmosphere. In addition, the consumer may come into contact with the fragrance liquid, because the fragrance liquid may seep through the holes in the perforated panel.
Many other common packaging materials, including some plastic films, are permeated by the fragrance before the desired release or are subject to attack by the fragrance itself or by its liquid carrier.
U.S. Pat. No. 4,634,614 issued to Holzner, relates to a peel system for a device for perfuming ambient air. The peel system comprises a delamination of a paper layer to separate a non-permeable lidding from a permeable membrane. In this invention, the paper layer does not provide a barrier to the aromatic product and some of the aromatic product is allowed to escape with time. In addition, the exposed membrane often has a poor appearance, as paper fibers may be left on the membrane when the package is peeled to activate the fragrance.
U.S. Pat. No. 4,145,001 issued to Weyenberg et al., and incorporated herein by reference, discloses a dispenser having a permeable membrane. The fragrance is sandwiched between the inner layers of two heat sealable panels. One of the inner layers is permeable to the fragrance vapors. The outer layers of the panels are impermeable to the fragrance and its vapors. The dispenser is opened by peeling back a panel along a release layer to expose the inner permeable layer. However, the permeable membrane layer disclosed in U.S. Pat. No. 4,145,001 has limited permeation for certain fragrances.
Other problems associated with permeable membranes are problems with machine operations. The most effective resins for permeation are often tacky in nature. The tacky nature of these resins often cause problems with the operation of the package machinery and processing steps, such as laminating, slitting and converting.
One objective of the present invention is an improved permeable multilayer membrane that provides greater controlled release over an extended period of time and increased permeation for a broader range of fragrances. Another objective is a multilayer membrane, which allows for the special selection of resins in the machine and tie layers to prevent problems associated with the operation of the package machinery and processing steps. Another objective of the present invention is to provide packaging for the fragrances and a means for exposing the membrane to the atmosphere at a desired time by consumer manipulation. A still further objective is to provide a release layer that has improved barrier to fragrances.